additional detour

An excellent short addition to this trip:

From Great River Bluffs SP, continue along Apple Blossom Scenic Drive from Nodine to LaCrescent (Winona Co Highway 1) which will take you through several Apple Orchard atop the Bluffs overlooking the River.

From there, get on MN-16 and take it all the way to back out to I-90 at Dexter, just east of Austin. MN-16 is the Historic River Bluffs National Scenic Byway. This route follows the Root River though several town, which are also linked with a very nice and popular paved bike path. This route also goes right by the previously mentioned Mystery Cave. However, if you are a fan of show caves, then I would actually recommend Niagara Cave in nearby Harmony MN which is a bit more touristy, but has several underground waterfalls and a few other interesting elements along the tour.